THE CLINICAL-ASSESSMENT OF ADIPOSITY IS A SUBSTANDARD PREDICTOR OF INSULIN SENSITIVITY AS ESTIMATED BY MINIMAL MODEL ANALYSIS

Fifteen male volunteers, aged 30 to 40 years old, were classified acco rding to body mass index (BMI) as lean (n = 5, BMI less than 20 kg/m2) , normal (n = 5, BMI 20-25) or obese (n = 5, BMI over 30). Glucose int olerance was ruled out by a normal oral glucose tolerance test and ins ulin sensitivity (S) and glucose effectiveness (S(G)) were estimated b y a minimal model analysis of a frequently sampled intrevenous glucose tolerance test modified by an intravenous insulin injection at minute 20. The MINMOD program was fed with 29 or 12 values (reduced sampling schedule). Despite a significant inverse correlation between BMI and S(I) (r = - 0,533 p < 0.05), the latter parameter overlapped among gro ups and the correlation was lost when obese individuals were not consi dered. Waist/hip ratio correlated modestly with S(I) (r = -0.52 p < 0, 05). S(G) did not correlate with BMI. Using the reduced sampling sched ule. S(I) values had a correlation coefficient of 0, 78 with those cal culated using the usual sampling schedule, although they were 82% lowe r. We conclude that only a BMI of over 30 accurately predicts a low S( I), and that waist/hip ratio does not have a better predictive power.